Three communities havinjg 4.2, 2.3 and less than 0.1 ppm flouride in the drinking water were chosen as study sites. Children 12-18 years of age who had been lifelong residents in the communities comprised the study populations. Plaque and saliva samples, collected from each participant, are being analyzed for microbial and fluoride content. DMF surfaces also were recorded for each participant. Data will consist of comparisons of various parameters among the three groups.